Conservation Partnerships Help a Small Fish Overcome Big Challenges

by Daniel Fenner

Arkansas River shiner.

Photo Credit: USFWS

Rivers of the southern Great Plains are among the most dynamic and harsh river environments in the world. Stream temperatures may reach over 100 degrees Fahrenheit during summer, while river flows range from overtopping their banks to long dry sections of river where only small isolated pools exist. This environment may not sound like suitable habitat for aquatic life, but many organisms including the Arkansas River shiner (Notropis girardi) are well equipped to handle these conditions.

Although the Arkansas River shiner is uniquely adapted to persist in this harsh environment, changes to Great Plains rivers over the last 40 to 60 years have caused the species to decline. The Arkansas River shiner was once widespread throughout the southern Great Plains, inhabiting over 3,200 miles of large sand bed rivers, such as the Arkansas River in Kansas, Oklahoma, and Arkansas; the Cimarron River, running through Kansas and Oklahoma; and the North Canadian and Salt Fork of the Arkansas River in Oklahoma. Today, the shiner is known to inhabit just 20 percent of its historic range—the South Canadian River from extreme eastern New Mexico through the Texas panhandle and downstream into Oklahoma.

In 1998, the Arkansas River shiner was listed as a federally threatened species, due to reductions of its range and numbers primarily attributed to habitat loss and modification through channelization, construction of impoundments, stream dewatering, diversion of surface water, groundwater pumping, and water quality degradation.

Biologists survey nearshore habitats for the presence of Arkansas River shiner.

Photo credit: USFWS

One significant challenge to Arkansas River shiner recovery is the species' complex life cycle, which has been impacted by the continued degradation of river flows. The fish, which is approximately the size of a pen cap and equal in weight to an aspirin tablet, moves upstream roughly 130 miles in the course of its 18-month life. After moving upstream and during the summer months, females release their semi-buoyant eggs into the water to be fertilized by sperm released by males. Once fertilized, eggs develop and drift downstream with the current for a couple of days before hatching, with an additional one to two days of downstream drift before the fish, considered prolarva at this point, is able to swim out of the current. If spawning occurs less than 130 miles upstream of an impoundment, eggs and prolarva will likely drop to the bottom of the impoundment, where they are likely to be covered in sediment and die.

While the development of impoundments has led to a significant decline of the species, new threats such as decreases in river flows may further hinder the species' ability to successfully reproduce. As an example, over the last 73 years, the South Canadian River near Amarillo, Texas has run dry a total of 362 days, with all but one of those dry days occurring within the last 30 years. Continued climate change, combined with increases in water demands from municipalities, agriculture, and oil, and gas operations may further impact river flows into the future.

Conservation partnerships focused on conserving the quantity and quality of water within the Arkansas River shiner's range are essential to the species' recovery. The U.S. Fish and Wildlife Service (Service) is working with other federal and state agencies, landowners, and other organizations to conserve water, maintain essential flows, and maintain riparian buffers to promote natural stream morphology and filter pollutants from entering the rivers in which the species depends. The Canadian River Municipal Water Authority, in cooperation with the Service, is working to control invasive salt cedar (Tamarix ramosissima), a thirsty plant known to affect water quantity and stream morphology, throughout the South Canadian River and its tributaries. Since 2004, over 26,000 acres of invasive salt cedar have been removed.

Fish surveys conducted by the Service in partnership with multiple state agencies including the Oklahoma Department of Wildlife Conservation and Oklahoma Department of Environmental Quality will help monitor the effectiveness of these on-the-ground efforts and provide information allowing the species recovery team to set goals for recovery. These partnerships and recovery efforts must continue moving forward to successfully conserve streams and rivers of the Southern Great Plains and aquatic life, which depend on free-flowing streams for their survival.

Daniel Fenner, a biologist in the Service's Oklahoma Ecological Services Field Office, can be reached at daniel_fenner@fws.gov or 918-382-4524.